Asil Nadir, for almost 20 years Britain's most famous fugitive from justice, has been found guilty of three counts of theft relating to his time as the boss of the Polly Peck empire which collapsed in 1990.

The 71-year-old, who built the sprawling, stock market-listed conglomerate from scratch, was accused of stealing almost £150m from the Mayfair-based group he allegedly ran "in an autocratic manner", according to the Serious Fraud Office, which brought the prosecution.

The trial has taken seven months, hearing evidence from many elderly and retired businessmen giving their recollection of events that took place more than two decades ago. The jury – down to just three women and seven men after two jurors were excused during marathon evidence sessions – deliberated for seven days before the judge indicated he would accept a majority verdict of nine to one.

At that point the jury indicated they had reached unanimous verdicts in relation to four of the 13 counts in the indictment against Nadir – acquitting him on one and convicting him on three. The jury are now continuing their deliberations in relation to the remaining counts.

During the trial, counsel for the SFO, Philip Shears QC, told the court of a wide pattern of repeated thefts, but said the prosecution focused on a small amount of that alleged behaviour relating to the transfer of £34m. Nadir denied all 13 charges.

Proceeds from years of alleged thievery are said to have gone on buying shares for himself, paying off personal tax bills and other debts linked to him or his associates.

At the start of the trial Shears explained to the jury why they were hearing evidence relating to events long forgotten by many. "Why are you trying matters so long ago? The answer is simple. He [Nadir] was due to stand trial in late 1993 but in May of 1993 he fled the country to northern Cyprus, thus leaving the jurisdiction, only to return in August 2010."

Nadir was a hero among City investors in the 1980s, rapidly transforming a sleepy East End rag trade firm into a multinational conglomerate with interests in food, electronics, textiles and leisure. Its best-known brand was the Del Monte fruit group, and among its directors was Sir Michael Sandberg.

At the heart of the prosecution case is a series of transfers to subsidiaries of Polly Peck in Turkey and Turkish-occupied northern Cyprus, which Shears said were disguised in order to mask the fact they were for the benefit of Nadir or his associates.

Operations in these two territories, especially those of Polly Peck's carton packaging firm Unipac, came to be the main profit generators within the group. However, they were also divisions over which Nadir allegedly had the most control. Unipac was run by Nadir's brother-in-law and was not audited by Polly Peck's accountants, Stoy Hayward.